1. Field of the Invention
The present invention relates to a gas compressor used in an air conditioning system and more particularly to a gas compressor that may enhance the refrigeration efficiency in the air conditioning system and may prevent the lubrication fault caused by oil shortage.
2. Description of the Related Art
As shown in FIG. 8, conventionally, in such a kind of the gas compressor, a compressor body 4, an oil separator 5 and the like are received in a casing 3 composed of a case 1 opened at one end and a front head 2 mounted on the open end. A space formed between the inside of the casing 3 and the front portion of the compressor body 4 is formed as a suction chamber 6, and a space formed between the inside of the casing 3 and the rear portion of the compressor body 4 is formed as a discharge chamber 7.
When a rotor 4b is rotated together with a rotor shaft 4a, the compressor body 4 sucks low pressure refrigerant gas from the suction chamber 6 into a cylinder 4d through a front side block 4c, compresses the low pressure refrigerant gas together with lubricant oil and discharges from a rear side block 4e toward the discharge chamber 7. Also, the oil separator 5 is mounted on the rear side block 4e of the compressor body 4 for separating high-pressure refrigerant gas, discharged from the compressor body 4 toward the discharge chamber 7, into a gas component and an oil component. The thus separated gas component passes from the discharge chamber 7 through a discharge port 7a of the case 1, a condenser 9 of an air conditioning system 8 shown in FIG. 9, an expansion valve 10, an evaporator 11 and the like and thereafter is returned to the suction chamber 6 from a suction port 6a to be again compressed together with the oil as the refrigerant gas. On the other hand, the oil component is temporarily reserved in an oil pool 7b at the bottom portion of the discharge chamber 7 and is again compressed together with the refrigerant gas.
However, in such a conventional gas compressor, although the high-pressure refrigerant gas discharged from the compressor body 4 is fed into the oil separator 5, it is difficult to completely separate the high-pressure refrigerant gas into the gas component and the oil component by the oil separator. As a result, the oil component that could not be completely separated (hereinafter also referred to as xe2x80x9cnon-separated oil componentxe2x80x9d) is caused to flow as a mist oil to the condenser 9 of the air conditioning system 8, the evaporator 11 and the like so that the oil circulation ratio (hereinafter also referred to as OCR) of the air conditioning system 8 is high and a large amount of the oil that inherently has nothing to do with the refrigeration is recirculated within the air conditioning system 8 to degrade the refrigeration efficiency. Also, when the oil component is caused to flow toward the condenser 9 of the air conditioning system 8, the amount of oil within the gas compressor is reduced to cause such a problem that the lubrication fault of the gas compressor due to the oil shortage would occur. Furthermore, in order to separate the gas component and the oil component of the refrigerant gas at a higher ratio, it is possible to consider using the combination in which the refrigerant gas and the oil are hardly mixed with each other. However, the oil that has been discharged from the gas compressor is cooled within the evaporator 11 and the like and the viscosity of the oil is increased so that the oil will not return to the gas compressor. Thus, there is a problem that the lubrication fault of the gas compressor due to the oil shortage would occur.
In order to overcome the above-noted defects inherent in the prior art, an object of the present invention is to provide a gas compressor that is suitable for enhancement of the refrigeration efficiency of an air conditioning system and to prevent the lubrication fault due to the oil shortage.
In order to attain the above-mentioned objects, according to the invention, there is provided a gas compressor comprising: a compressor body for compressing a refrigerant gas in a suction chamber together with oil for lubrication and for discharging this to the side of a discharge chamber; and an oil separator for separating high-pressure refrigerant gas discharged from the compressor body into a gas component and an oil component, in which the gas component returns to the suction chamber from the discharge chamber through a condenser or the like of an air conditioning system to be compressed again together with oil as the refrigerant gas, and the oil component is temporarily reserved in an oil pool of the bottom portion of the discharge chamber to be compressed again together with the refrigerant gas, characterized in that a space volume is enlarged enough to suppress an oil circulation ratio of the air conditioning system and to keep a sufficient amount of oil within the gas compressor body.
According to the present invention, there are provided a casing for receiving the compressor body and the oil separator. A space defined between the inside of the casing and the front portion of the compressor body is formed into a suction chamber, and a space defined between the inside of the casing the rear portion of the compressor body is formed into a discharge chamber. The space volume of the above-described discharge chamber is enlarged by projecting the inside of the casing to the outside.
According to the present invention, there is provided a gas compressor comprising a plurality of compressor bodies and a single discharge chamber, in which the refrigerant gas in each suction chamber is compressed together with the oil for every respective compressor bodies to be discharged to the single discharge chamber by separating this into a gas component and an oil component, the gas component returns to the suction chamber from the single suction chamber through the condenser or the like of the air conditioning system to be compressed again as the refrigerant gas together with the oil, and the oil component is temporarily reserved in the oil pool of the bottom portion of the discharge chamber to be compressed again together with the refrigerant gas, characterized in that a space volume of the single discharge chamber is enlarged enough to suppress an oil circulation ratio of the air conditioning system and to keep a sufficient amount of oil within the gas compressor body.
The gas compressor according to the invention is characterized in that the discharge chamber has a space volume that is two times to ten times larger than a sucked gas displacement per one revolution of the compressor body.
The gas compressor according to the invention is characterized in that the single discharge chamber has a space volume that is ten times to thirty times larger than a sucked gas displacement per one revolution of a plurality of body.
The gas compressor according to the invention is characterized in that the combination of the oil and the refrigerant gas is one selected from a group essentially consisting of PAG system oil and R22 refrigerant, PAG system oil and R407C refrigerant, ether system oil and R407C refrigerant, carbonate system oil and R407C refrigerant, carbonate system oil and R410a refrigerant, ester system oil and R410a refrigerant and PAG system oil and R134a refrigerant.
According to the present invention, since the space volume of the discharge chamber is large as described above, the high-pressure refrigerant gas including the oil component (non-separated oil component) that could not be separated by the oil separator is stagnant in the discharge chamber for a long period of time. The ratio of the non-separated oil component to drop by its gravitational force down to the oil pool at the bottom of the discharge chamber to thereby considerably reduce the entrance amount of the non-separated oil component to the condenser, the evaporator and the like of the air conditioning system.
Note that, in the present invention, the oil circulation ratio or OCR means the ratio of the oil component amount relative to the entire amount of the mixture of the refrigerant gas component and the oil component at any desired position within the air conditioning system except for the compressor when a part of the oil filled within the compressor is discharged to the air conditioning system by the operation of the compressor. Also, the sucked gas displacement volume per one revolution of the compressor means, in the structure where the refrigerant gas is compressed by the compressor body due to the rotation of the rotor, a theoretical volume of the sucked gas, to be discharged during one revolution of the rotor, which may be calculated in accordance with a dimension and a structure of the compressor body. The PAG is abridgement of polyalikylene glycol.